The Talmud debates if we shouldn't start after Ma Nishtana (The four questions) with the good news, starting with redemption. "The Jews came out of Egypt", and then go back and explain why we were redeemed, instead of starting off with "We were slaves..."
No, we'd rather end on a good note, even if that means starting from the bad news.
Which bad news do you start from? From the time when we slaves to Pharaoh in Egypt? Or from the time when we were living in the land of Canaan and were Idol worshippers? That's really the true beginning.
The Gemorah says that because the questions are geared towards Egypt, you start with Egypt.
Avadim Hayiinu lays out the historical problems of the Jews with the second sentence:
If G-d would not have removed us from Egypt than we and our children and our children's children would still be slaves to Pharaoh in Egypt.
How can we say in all seriousness that we'd still be there? Who knows? Anything could have happened, Egypt could have fallen, as happens with empires. We could have walked out. There are plenty of potential negatives, why hypothesize this one?
The story goes (Exodus 12:34-37): that when the Jews went out they took gold, silver, clothing, and emptied Egypt out. Then it goes on to say that they took livestock.
Why mention livestock separately from gold and silver, etc.?
One answer from some of the Rabbis is that there's a question of where did the Jews in the desert get the livestock to do sacrifices. This statement is to establish where they got it from.
But the Midrash says that Jacob put away lumber which the children of Israel carried away when they left Egypt and they used that lumber to build the Tabernacle. No one asks "where did that wood come from?" yet surely it would have been harder to come by wood in the desert than to come by livestock. So if the question is "Where did the Jews get the supplies to worship G-d," why mention livestock, but not lumber?
Continuing with the story in Exodus, what right do the Jews have to empty Egypt? It seems rather hard luck on the Egyptians. In the commentary on the verse, Rashi brings up the issue of severance pay which is built into the system of how you deal with an employee.
From Deuteronomy 15:13-14 : You can't send someone who works for you away empty handed, you will give him from your flocks and your fields, and you shall remember that you were a slave...
Tying back to our point, G-d sets up the parallel between being a slave in Egypt and this concept of severance. We are obligated to give severance pay to our employees because when we were slaves and we were fired, kicked out of our jobs, G-d gave us severance commensurate with the years that we worked in Egypt.
When G-d reimbursed the Jews, it says that they he reimbursed them from the waters, and the land. As an analogy, Tel Aviv was in dispute as to whether it was considered part of the Holy Land Israel or as Diaspora, because it was under water in Biblical times. Therefore Rabbi Java said that you should celebrate in Tel Aviv like it's in the Diaspora, because it didn't exist. Halacha follows the majority opinion which holds that Tel Aviv is part of Israel, and that ruling is based on notion from Rashi that the text "the spoils of the sea" shows that the borders of the land do not terminate the obligations of severance pay.
In Kiddushin (Gemorah), they make the point that severance comes from the commodity of the country: which in the case of Egypt would be livestock (and of course the law in Deut, which states flocks, fields, and wine). But how do you know to give more than just flock, and wine, and grains? Because the Torah continues "from whatever G-d blessed you" so it is not restricted to those three items. What makes these items unique, and worthy of special attention?
They are unique in that they have the quality of reproduction. You give someone sheep, or a grain, or grapes, they can either consume them immediately, or cultivate them to provide additional benefit in the future. That's why the Torah does not specifically mention cash which does not have the same ability to be cultivated.
So given this new understanding, wouldn't livestock be mentioned first as the most important thing that they took?
If an employee resigns, there's no obligation to pay severance. The only time you're obligated to pay severance is when you ask your employee to leave. So back to our original question: Why would we still be slaves to Pharaoh in Egypt if G-d hadn't taken us out? We wouldn't have gone. We would have no right of severance, we would have had to leave with nothing, and so we wouldn't have left. Therefore G-d gave 10 plagues to get the Egyptians to want the Jews to leave, and activate the law of severance.
The Haggadah seems to deliberately skew the question this way, to point of law so it does not have to address the idea that the Jewish people themselves might have been lost had they stayed in Egypt.
So we have to ask ourselves, can the Jewish people disintegrate?
So far, we've been a community that has survived everything.
But the Haggadah says, if G-d didn't take out of Egypt, we might disintegrated. But why might that be true? History has shown that we haven't disintegrated, and that's why the Haggadah moves away from that point.
The Kuzri (book - conversation between King and Scholar, trying to understand Judaism) brings out that the point that it is because of our observance of Shabbos and festivals, we have separated ourselves from the other nations which allow us to keep our identity, rather than become assimilated into the collective society. It reemphasizes the point that if G-d didn't intercede for us, we would still be identifying in Egypt into the identity that Egypt chose for us, rather than cultivating our own identity.
Gemorah Makkos speaks of the four visions that Moses had about the Jewish people
One of them was "And you perish among the nations."
That if the Jews left Israel, they would not survive among the nations. The only future for Judaism was to be united in the land of the Israel.
Isaiah disagreed and he wrote about the first exile, "On that day the great Shofer will be blown, those who are lost in Assyria will come back."
Does this nullify the prophesy of Moses?
Rav (500 years after Isaiah, at beginning of Babylonian exile) says that he's concerned about the Jews perishing among the nations. Isaiah's prophesy has come true, they returned after the first Temple was destroyed, but this is different. Maybe Isaiah was right about the first exile, but Moses is referring to the second exile.
The Gemorah doesn't want to theorize that Jews could have been lost in Egypt, they want to go a different way, because they want the prophesy of Moses to be nullified. There has been a way for the Jews to band together through every tragedy, even without revealed miracles (like the red sea).
The Or Ha'Chayiim writes a commentary on the first line of the 10 commandments (Exodus 20:2 I the L-rd, am your G-d who brought you from the land of Egypt, from the house of bondage.). He wonders about the double language "Egypt"+House of slavery. It's a little redundant on its face. But the Or Ha'Chayiim explains that they were redeemed both in body and in mind. The Jews could have been taken out of Egypt, but still considered themselves slaves, and they could have been taken out of Egypt but had the status of escaped slaves. But this is what G-d did:
1) He made Pharaoh dismiss them, so they were not slaves.
2) He drowned they Egyptians in the seas so they would be unable to come back and claim that they were escaped slaves.
Without the aid of G-d, not only would the Jews not have left Egypt, but they would also not have been able to escape the slave mentality. So G-d had to take them out of Egypt and refresh their minds and reestablish the spiritual connection. We would not mentally have been able to reshape ourselves. We would have been restricted to other people's impressions of us, in a sense.
Because G-d redeemed us, we are able to have our own spiritual connection, unsullied by the environment around us. See David in Chronicles "who is like your people Israel, a unified nation even on earth."
R Naftali of Rupshitz says offers a dissenting opinion from the Or Ha'Chayiim. He proposes that G-d took the Jews out of Egypt in a moment, but the 40 years of wandering in the desert was to take Egypt out of the Jews. The spiritual redemption of the Jews must come from inside, and must be the life's work of a Jew.
R. Yisrael of Tchortchotov reconciles the two opinions by pointing out that there are two dimensions of exile: material, and spiritual. G-d can take us out of the physical exile, but we could not have freed us from our mental exile without the strength and awareness given to us by G-d during the Exodus. Compare this sound of Shofer on Yom Kippur. G-d's redemption is a wakeup call, and after that, we must work to maintain what G-d has awoken.